Photocatalytic degradation of paraquat using TiO₂ /RH-SiO₂

Abstract

TiO₂/RH-SiO₂ photocatalysts were successfully prepared by impregnation of TiO₂ colloid solution on silica, extracted from rice husk. The calcined catalysts at 500°C for 5 hr showed only the anatase phase of TiO₂ along with the amorphous phase of RH-SiO₂. For the photocatalytic performances on the decomposition of paraquat under UV irradiation, silica assisted the performance by the adsorption phenomena fitted with Langmuir behavior. The study on pellet fabrication of catalyst was found that mechanical coating method provided higher paraquat adsorption than pressing method. For the degradation part, 10 wt% TiO₂/RH-SiO₂ catalyst yielded the highest efficiency of paraquat degradation. The reaction was fitted with LHHW model. The catalyst pellet fabrication for both cases, including mechanical coating and pressing, was inapplicable for the use. The deforming of pellet was a main factor.